Discharging a. fire extinguishing medium



NOV. 1, 1932- w Y N 1,885,817

DISCHARGING A FIRE EXTINGUISHING MEDIUM Filed July 24, 1928 awwautoz Z2 M05143?? Patented Nov. 1, 1932 UNITED STATES PATENT OFFICE WALTER FBEYGANG, OF WEEHAWKEN, NEW JERSEY, ASSIGNOR TO WALTER KIDDE & COMPANY, INC., 015 NEW YORK, N. Y., A CORPORATION OF NEW YORK DISCHABGING A. FIRE EXTINGUISHING MEDIUM Application filed July 24, 1928. Serial No. 295,054.

The present invention relates to a method for extinguishing fires, particularly one in e which a speedy discharge of the extinguishing medium is obtained. Unlike the generally accepted practice, this invention does not follow the principles usually adhered to in accordance with which discharge piping has been used, the inside diameter of which is substantially uniform. By eliminating restrictions in the piping, freezing and consequent clogging has been avoided and-the extinguishing medium has thus been delivered in liquid form to the outlets. Fearof freezing and clogging has, in this manner, limited the ability to discharge the medium as quickly as might be desired under certain circumstances.

Contrary to the above theory, the present invention proposes to use a large bore continuation piping which receives the fire extinguishing medium from a relatively smaller bore supply pipe, a suitable fitting being provided to connect the supply and continuation piping. This results in an appreciable drop in pressure at the entrance of the large bore pipe and a corresponding increase in the volume of the medium discharged over a given period of time.

Upon expansion, partial gasification takes place and both the liquid and gas are carried forward in the pipe, accompanied by a fall in temperature and pressure. As the pressure reaches 78 pounds per square inch absolute (the triple point for carbon dioxide), a portion of the liquid freezes and the medium is in the form of snow as well as in fluid form, that is as liquid and gas. In the further travel of the medium, accompanied by a continued fall in temperature and pressure, the liquid is entirely transformed into snow and gas and below the pressure of 78 pounds per square inch absolute there is no liquid presentin the pipe. In this manner, the discharge is composed of gas and snow only, and the continuation pipe should be of a character such that no obstructions will be present which will cause clogging thereof due to collection of the snow.

An object of the invention is, therefore,

to provide a method of discharging a fire extinguishing medium, such as carbon dioxide stored in liquid form, more rapidly from its containers than has been possibl heretofore. Without disturbing the standard discharge valve and releasing mechanism of the containers, the medium is discharged into a large bore continuation piping before reaching its triple point, the ratio of the areas of the supply piping and continuation piping being within certain well defined limits to produce a rapid discharge under the most favorable conditions.

A further object of the invention is to provide a system of the above character wherein the medium, after expansion, 1s carried through a continuation piping'in which no contractions or enlargements are permitted such as would cause the collection of snow with consequent clogging. It is contemplated that the triple point of the medium will be reached during its movement through the continuation piping and that snow may be discharged with the gas at the outlet of the continuation piping Further objects will appear as the de scription of the invention proceeds and reference will now be had to the accompanying drawing, wherein the single figure is a view in elevation, partly in section, showing a discharge system constructed to discharge the fire extinguishing medium in accordance with the method disclosed herein.

I Referring to the above figure, a designates a suitable container for a supply of carbon dioxide which is maintained in liquid form under pressure. Pipe a. takes the liquid from the bottom of the container and conducts it to a discharge valve a from which it is delivered to a supply pipe I). A continuation pipe 0, of greater diameter than the supply pipe, is connected to the supply pipe by means of a fitting d, as will be seen from the drawing.

Exhaustive tests have shown that the ratio of the areas of the supply pipe to the continu- A ation pipe should be approximately 1 to 3, the limiting values of such ratio being 1 to l and 1 to 5.

The fitting d is formed with a threaded recess d to receive the supply pipe which is of relatively small diameter, and a threaded recess d to receive the larger diameter "continuation pipe. An annular flange (i may be provided to serve as an abutment for the supply pipe and to form an orifice through which the medium is discharged. As expansion takes place and the medium in fluid form passes through the continuation pipe 0, the pressure thereof will drop, as will the temperature, and the triple point will be reached at some point in the pipe 0 nearer its outlet and carbon dioxide snow will be formed. The carbon dioxide snow is carried along with the medium to the end of the pipe where it is discharged in the usual manner. There is no need to take the precaution of preventing expansion in the pipe 0 except that, once the triple point is reached and snow formed, no such contraction or enlargement must be allowed as would permit the collection of snow with consequent clogging.

It will be understood that in the contemplation of this invention the orifice at d is not a relatively very small orifice, such as has been commonly used in controlling the flow of a fire extinguishing medium, such as carbon dioxide, under great pressure, but must be such that it does not materially reduce the rate of How in the piping leading up to the orifice. Its area is preferably equal to that of the piping, but may be less.

The rate of discharge increases in proportion to the ratio of the area of the continuation piping to the area of the supply pipe and, as stated, the most efiective ratio has been found to be that of 3 to 1. No claim is made broadly to the expansion of the medium flowing from the supply pipe but only to the specific method and apparatus claimed hereinafter.

I claim as my invention: e

1. A fire extinguishing medium discharge system comprising a container, supply piping for removing the medium from the container and of such diameter and capacity as to-prevent the pressure of the medium from falling to the triple point within it, continuation piping of substantially uniform diam- I eter and of from one to five times the area of the supply piping, and a fitting connecting the supply and continuation piping and including an orifice through which the medium tinuation piping and including an orifice, said orifice having an area such that it does not restrict materially the flow of the medium through the supply piping, and the continuation piping having an area in crosssection substantially three times the area in cross-section of the supply piping.

3. A fire extinguishing medium discharge system comprising a container, supply piping for removing the medium from the container and of a diameter and capacity such as to' prevent the pressure of the medium from falling to the triple point within it, continuation piping of larger diameter than the supply piping and of such diameter and capacityas to prevent the pressure of the medium from falling to the triple point adjacent the supply piping, and a connection between thesupply and continuation piping, the connection being such that it does not restrict materially the flow of the medium through the V supply piping.

4. A fire extinguishing medium discharge system comprising a container, supply piping for removing the medium from the container and of a diameter and capacity such as to preventthe pressure of the medium from falling to the triple point within it, continuation piping of larger diameter than the supply piping and of such diameter and capacity as to prevent the velocity of the medium falling below an amount suflicient to hold substantially the entire solid formation in suspension while in the piping, and a connection between the supply and continuation p p 5. A fire extinguishing medium discharge system for discharging a medium under pressure from a container, comprising supply piping for removing the medium from the contalner and of a diameter and capacity such as to prevent the pressure of the medium from falling to the triple point within it, continuation piping within which the pressure of the medium falls to the triple point but of such diameter and capacity as to prevent the velocity of the medium falling below an amount sufiicient to hold substantially the entire solid formation in suspension while in the piping, and a connection between the p supply and continuation piping.

This specification signed this 20th dayof July, A. D. 1928. i

WALTER H; FREYGANG. 

